RPA running on computer, but nothing is happening (works on other user's computers)

I have developed an RPA in studio and it has been quite the success, so now, users in my company want to get to use the automation. The automation runs perfectly on my laptop (both from studio and the assistant), as well as, on a common computer in the office, which is logged in with another than mine.
A user then want the automation to run on his computer - He runs it from the assistant and has an attended license attached with his user.
When he runs the automation, the robot starts running and the assistant shows, that the robot is being run and then, nothing.
The robot is supposed to start with showing a form to the user. To be able to display this form, the computer it is run on needs .Net 5.0 - His has that.
When the robot is run by his user, the logs states, that the robot has been run successfully - Tho, he tends to stop the automation after several minutes without nothing happening.
I can’t not figure out, why nothing is happening - To me, nothing seems wrong. Would any of you have an idea, of what could be the issue?

Thank you in advance!

Try to run a small work flow in his machine

Does work, however, the flow with the form in it does not?